was a distinguished Kyoto lineage of swordsmiths that flourished from the period through the period. The first-generation belonged to the Ryokai line, and tradition holds that he studied under Sadamune; dated works are known from the Enbun, Koan, and Joji eras. Thereafter, successive generations using the name are recognized toward the end of the period, and in the early period there appeared the so-called Oei , namely Saemon no Jo and Shikibu no Jo . During the period alone, two or three smiths using the name are thought to have been active, with the line continuing into the Oei era.
Across the generations, the workmanship presents two principal modes: reflecting the Kyo-mono tradition, and inheriting Sadamune's style. From the late successors through the Oei , however, one can additionally observe a newly developed range of irregular temper based primarily on . The is characteristically mixed with , tightly forged, with thick and frequent . The in the -flavored mode mixes with -shaped elements -- a trait that distinctly manifests the special characteristics of this lineage. and run through, and the is bright. The typically enters in with and . The character "" written in the left-form style appears from around the Shitoku-Meitoku years and is frequently encountered in works of the Oei era.
The superimposed () executed on both sides of many works is consistently praised as magnificent, harmonizing well with the blade and enhancing the overall effect. Both and are repeatedly noted as being in condition, and the line's signed works, including the valuable Meitoku date inscription, constitute important reference material for the study of Kyoto swordsmithing.
